Electrical conduit that is run vertically in building studs is held in place by ties which grip the conduit to the stud through holes punched in the studs. The holes are generally punched by hand with a hammer and awl or hand-held punch. In recent years C-shaped metal studs have been used in construction with the conduit run down the channels. A pair of holes are punched in the center sheet piece at intervals and the conduit is tied to the metal studs at each set of holes. At times the conduit is held to the studs by ties that are held to the stud sheet by screws. The punched holes are often off-size, either too large or too small or incompletely punched. When screws are placed in such holes, they sometimes will not bite or hang loosely from the stud. Also, the studs can be damaged by incorrectly punched holes. In addition, electrical mounting boxes are mounted at the bottom of the studs by a number of screws. Holes for the mounting screws are also hand punched through the studs in the same manner described above with the same problems resulting.
Ordinary locking hand tools, however, are not able to extend around the stud flanges to the center of the sheet of the C-shaped studs, so that awkward two-tooled methods continue to be used in the construction industry.
A C-clamp locking hand tool is capable of approaching both sides of the center member of a C-channel with ease. Locking hand tools, however, do not have punching capabilities. A locking hand tool, on the other hand, operates on the principle of the toggle, which can be the basis for a driving capability adaptable for punching.
One patent which describes a punching tool operated by a toggle drive is described in U.S. Pat. No. 1,674,844 issued June 26, 1928 to H. Spengler, which describes a toggle that is arranged to be opened and closed in the opening and closing movements of a pair of levers provided at their free ends with hand grips. The punch is operated through the punching stroke by bringing the handles together, the toggle being opened in this operation. The punch is retracted when the handles are moved apart.
Another patent that describes a punching tool by a toggle-type drive is described in U.S. Pat. No. 1,685,604 issued Sept. 25, 1928 to J. Jensen, which describes a lever and an arm each having handles at their free ends. The lever drives a rocker lever having a punch by a toggle-type mechanism, bringing the handles together, the toggle being opened in this operation. The punch is retracted when the handles are moved apart.
Other patents which describe hand punch tools are as follows:
______________________________________ Inventor U.S. Pat. No. Date of Issue ______________________________________ Gates 126,141 Apr. 30, 1872 Morrill 279,493 June 12, 1883 McGill 351,645 Oct. 26, 1886 Avery 387,133 July 31, 1888 Keighley 566,402 Aug. 25,1896 Philippi 818,783 Apr. 24, 1906 Kidder 834,139 Oct. 23, 1906 Goddard 893,071 July 14,1908 Whitney 898,397 Sept. 8, 1908 Blum 902,643 Nov. 3, 1908 Goddard 1,036,896 Sept. 10, 1912 Whitney 1,065,752 June 24, 1943 Valentine 2,359,699 Oct. 3, 1944 Klenk 3,261,073 July 19, 1966 Hamel 3,261,073 Aug. 6, 1968 Deike 3,939,563 Feb. 24, 1976 ______________________________________
Certain patents which describe locking hand tools are as follows:
______________________________________ Inventor U.S. Pat. No. Date of Issue ______________________________________ W. Petersen 1,489,458 Apr. 18, 1924 W. Petersen 2,201,918 May 21, 1940 W. Petersen 2,280,005 Apr. 14, 1942 Borchers 2,299,454 Oct. 20, 1942 Toernberg 2,341,489 Feb. 8, 1944 W. Petersen 2,417,013 Mar. 4, 1947 C. Petersen 2,563,267 Aug. 7, 1951 C. Petersen 2,590,031 Mar. 18, 1952 W. Petersen 2,711,663 June 28, 1955 W. Petersen 2,853,910 Sept. 30, 1958 Hostetter Re. 26,280 Jan. 7, 1964/ Oct. 17, 1967 C. Petersen et al 3,192,804 July 6, 1965 Schroeder 3,585,704 June 22, 1971 Marasco 3,590,669 July 6, 1971 Baldwin 3,600,986 Aug. 24, 1971 C. Petersen 4,541,312 Sept. 17, 1985 C. Petersen 4,546,680 Oct. 15, 1985 ______________________________________
It is the object of this invention to provide a C-clamp locking hand tool with punching capability that can be used to punch holes in sheet metal difficult to access.
It is another object of this invention to provide a C-clamp locking hand tool with opposed mounts for punching holes in the main sheet of a C-shaped metal stud.
It is another object of this invention to provide a hand tool which is capable of quickly and easily punching holes in a metal stud with one hand.